SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677ff2c21287fc54a844827a3249bb293289751d1189da8683d8d3072b6f8eaf' 
  AND token = 'cdt5/qAB3urqTWuZmiAKK3FfqOC4QFMHgrUEnq5oVxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}